In Closed Circuit Mixed Gas Diving and/or other SCUBA diving applications, wherein a diver is breathing different levels of oxygen, nitrogen, helium and sometimes carbon dioxide, it becomes important that a diver be notified of certain dangerous conditions in the breathing gas or when the amount of a breathing gas is low. In the prior art, divers typically monitor levels and amounts of gas by meters, gauges and electronic displays that are secured to a diver and audible alarms. The prior art also employs light systems, which can be seen by a diver while breathing the gas of a system and provide a visual warning.
The meter, gauges and display systems mounted on the arm or other area on the diver do not effectively alert the diver to dangerous conditions, since they cannot be constantly monitored by the diver.
One problem with alert systems found in the prior art that feature only a light notification, such as a flashing bulb or activation of a LED, is that it can be obscured by other bright lights from another diver or the sun in shallow or clear water.
Auditory (“beeper”) type alarms have been used in numerous diving systems for years. The disadvantage to such systems is that often circumstances are such that an individual diver cannot hear the alarm, or mistakes others alarms for his own, or vice-versa, resulting in the diver ignoring the alarm he hears.
In the prior art, most underwater alarm systems utilized audible alarms to indicate problems that the individual diver has with his system. These alarms could often be unheard (due to various factors, such as external hoods being worn by the diver) and were often mistaken for other alarms being transmitted by other diver's units in a group diving situation, resulting in confusion. Vibrating alarms have also been used in similar applications with similar shortcomings.